Continued angular basic process

skais/ais/ais_trajectory.py

@@ -5,7 +5,7 @@ import numpy as np
 from numba import jit
 from scipy.interpolate import interp1d
 
-from skais.stats.angluar import angular_dispersion
+from skais.process.basic_features_operations import angular_dispersion
 from skais.utils.geography import great_circle
 from skais.utils.stats import calc_std_dev
 

skais/process/basic_features_operations.py

+import numpy as np
+
+
+def angular_average_vector(angles):
+    n = len(angles)
+    x = np.sum(np.cos(angles)) / n
+    y = np.sum(np.sin(angles)) / n
+
+    return np.array([x, y])
+
+
+def angular_dispersion(angles):
+    x, y = angular_average_vector(angles)
+    return np.sqrt(x ** 2 + y ** 2)
+
+
+def angular_mean(angles):
+    x, y = angular_average_vector(angles)
+    theta = abs(np.arctan2(x, y))
+
+    if y > 0 and x > 0:  # first Q
+        return theta
+    if y > 0 >= x:  # Second Q
+        return np.pi / 2 + theta
+    if y <= 0 < x:  # Fourth Q
+        return np.pi / 2 - theta
+    else:  # Third Q
+        return - theta
+
+
+def angular_std(angles):
+    return 1 - angular_dispersion(angles)
+

skais/stats/angluar.py

-import numpy as np
-
-
-def angular_dispersion(x):
-    n = len(x)
-    X = np.sum(np.cos(x)) / n
-    Y = np.sum(np.sin(x)) / n
-
-    r = np.sqrt(X ** 2 + Y ** 2)
-
-    return r
-
-
-def angular_mean(x):
-    n = len(x)
-    X = np.sum(np.cos(x)) / n
-    Y = np.sum(np.sin(x)) / n
-
-    theta = abs(np.arctan2(X, Y))
-
-    if Y > 0 and X > 0: # first Q
-        return theta
-
-    if Y > 0 >= X: # Second Q
-        return np.pi/2 + theta
-
-    if Y <= 0 < X: # Fourth Q
-        return np.pi/2 - theta
-    else: #Third Q
-        return - theta

skais/tests/stats/test_angular.py → skais/tests/process/test_basic_features_operations.py

@@ -2,7 +2,7 @@ import unittest
 
 import numpy as np
 
-from skais.stats.angluar import angular_mean
+from skais.process.basic_features_operations import angular_mean, angular_std
 
 
 class TestAngular(unittest.TestCase):
@@ -40,3 +40,13 @@ class TestAngular(unittest.TestCase):
         x = np.radians(np.array([313, 314, 315, 316, 317]))
 
         self.assertEqual(-np.pi / 4, angular_mean(x))
+
+    def test_angular_std(self):
+        x = np.radians(np.array([0, 0, 0, 0]))
+
+        self.assertEqual(0, angular_std(x))
+
+    def test_angular_std(self):
+        x = np.radians(np.array([0, 90, 180, 270]))
+
+        self.assertAlmostEqual(1, angular_std(x))
\ No newline at end of file